Mug coaster



FIG. 1 is a perspective view of a mug coaster showing my new design;

FIG. 2 is a trop plan view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a side elevation view thereof;

FIG. 5 is an opposite side elevation view thereof;

FIG. 6 is a front elevation view thereof; and,

FIG. 7 is a bottom plan view thereof. 

The ornamental design for a mug coaster, as shown. 